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ARS Home » Plains Area » Fargo, North Dakota » Edward T. Schafer Agricultural Research Center » Sunflower and Plant Biology Research » Research » Research Project #439100

Research Project: Biology of Weed-Crop Interactions to Improve Weed Management Strategies in Northern Agro-ecosystems

Location: Sunflower and Plant Biology Research

Project Number: 3060-21220-033-000-D
Project Type: In-House Appropriated

Start Date: Oct 1, 2020
End Date: Sep 30, 2025

Objective 1: Determine the nature of inter and intraspecific competition and extent of crop yield loss among relay or double cropped agricultural plant species in comparison to natural weed competition. Sub-objective 1A: Identify, under field conditions, the genes that are differentially regulated by natural weed populations, cover crops, and intra-specific competition in sunflower (Helianthus annuus). Sub-objective 1B: Examine the impact of intra-specific competition on sunflower and corn (Zea mays L.) yield loss and gene expression under controlled conditions Objective 2: Identify genetic or biochemical signals associated with interspecific competition and determine the associated biological mechanisms that can be used as targets for genetic manipulation. Sub-objective 2A: Create constructs from corn promoters to identify the transcription factor(s) binding sites regulating weed- and/or cover crop-inducible genes. Sub-objective 2B: Test if changes in salicylic acid levels corresponds to weed perception in corn. Sub-objective 2C: Utilize the weed inducible promoter from corn to suppress the salicylic acid signaling during weed-crop or crop-cover crop interactions under controlled greenhouse conditions. Objective 3: Functionally characterize specific targets impacting interspecific competition for genetic manipulation of weed tolerance, winter survival, early maturation, and/or response to bioherbicides. Sub-objective 3A: Identify winter hardy canola and camelina germplasm that also have an early maturity trait for reducing competition between the cover crop and the relay-crop. As a first step, we will map early maturation Quantitative Trait Loci (QTLs) in a segregating Recombinant Inbred Line (RIL) population of Camelina sativa. Sub-objective 3B: Determine if the freezing tolerance genes identified from winter camelina will increase freezing tolerance in canola (Brassica napus L.). Sub-objective 3C: Functionally characterize the weed-induced PIF3 genes in soybean (Glycine max (L.) Merr).

Integrated weed management (IWM) is considered the most effective approach for managing weeds. In the northern Great Plains, incorporation of winter-hardy crops or cover crops as components of IWM systems are gaining popularity as an approach for managing weeds and the spread of herbicide resistant weeds. However, just like weeds, inter-specific competition with winter crops or cover crops, when used in multi-cropping systems, results in yield losses in major commodities. In this project, multi-cropping refers to fall-planting of oilseed cover crops that overwinter and are terminated or harvested prior to planting a primary summer commodity crop (double-cropping) or a primary commodity crop inter-seeded into the cover crop such that their life cycles overlap (relay-cropping). Factors impacting competition-induced yield losses have only been evaluated in a limited number of traditional multi-cropping systems under field conditions and this gap in knowledge needs to be addressed as new cropping and IWM systems suitable for the northern Great Plains are developed. To generate new knowledge for regionally-appropriate IWM approaches, the goals of this project are to: 1) understand how major commodity crops perceive and respond to inter- and intra-specific competition, 2) identify genes regulating winter survival and early maturity that can be manipulated to improve these traits in winter crops and cover crops, and 3) identify targets for mitigating competition-induced yield losses through breeding or genetic manipulation. Being able to multi-crop major commodities with winter-hardy crops or cover crops without resulting in yield loss, or mitigating weed-induced yield losses in general, would provide new IWM options. Thus, the objectives of this project will address gaps in our knowledge that limit the ability to develop sustainable IWM approaches appropriate for agricultural intensification in the northern Great Plains.